<h1>SetBackgroundColor</h1>

<p>SetBackgroundColor sets the background colour displayed in every frame in 
the movie.</p>

<table>

<tr>
<th nowrap>Field Name</th>
<th>Type</th>
<th>Size</th>
<th>Description</th>
</tr>

<tr>
<td nowrap valign="top">type</td>
<td nowrap valign="top">unsigned bit</td>
<td nowrap valign="top" align="right">10</td>
<td>Identifies the SetBackgroundColor instruction when it is encoded. It is 
encoded with the length field as a 16-bit integer (Little-endian byte order).</td>
</tr>

<tr>
<td nowrap valign="top">length</td>
<td nowrap valign="top">unsigned bit</td>
<td nowrap valign="top" align="right">6</td>
<td>The length in bytes of the body of the instruction when it is encoded. If the length is greater 
than 62 then this field is set to 0x3F and the length is encoded using the 
extendedLength field. Encoded with the type field as a 16-bit integer.</td>
</tr>

<tr>
<td nowrap valign="top">extendedLength</td>
<td nowrap valign="top">unsigned int</td>
<td nowrap valign="top" align="right">32</td>
<td>Optional. Contains the length in bytes of the encoded instruction if it is
greater than 62 bytes. If the length is 62 bytes or less then this field is 
omitted.</td>
</tr>

<tr>
<td nowrap valign="top">color</td>
<td nowrap valign="top">Color</td>
<td nowrap valign="top" align="right">&nbsp;</td>
<td>The background colour displayed in each frame of the movie.</td>
</tr>

</table>

<p>The Color only specifies a background that is completely opaque - the alpha 
channel information in the Color is ignored.</p>

<p>The extendedLength field is included for completeness. Since a Color is only 
3 bytes (transparency is not supported) the extendedLength field would never be
used in practice. It is possible to encode a SetBackgroundColor instruction 
using this field however.

<p>The background colour must be set before the first frame is displayed otherwise 
the background colour defaults to white. This is typically the first object in 
a Flash file. If more than one SetBackgroundColor instruction is added to a movie 
then only first one sets the background colour. Subsequent objects are ignored.</p>

<h2>History</h2>

<p>The SetBackgroundColor instruction represents the SetBackgroundColor tag from the 
Macromedia Flash (SWF) File Format Specification. It was introduced in Flash 1.</p>
